The invention relates to an image sensor and a manufacturing method thereof.
The image sensor is a semiconductor device for converting an optical image to an electrical signal, and includes a CCD (charge coupled device) image sensor and a CMOS (complementary metal oxide silicon) image sensor.
The CMOS image sensor includes a photodiode and at least one MOS transistor in each unit pixel, and sequentially detects electrical signals of each unit pixel in a switching mode to realize images. The CMOS image sensor may have a structure in which the photodiode (which converts a received light signal to an electrical signal) and the transistor(s) (which process the electrical signal) are horizontally disposed on a semiconductor substrate. According to the horizontal CMOS image sensor, the photodiode and the transistor are horizontally adjacent to each other on a substrate. Thus, an additional area for forming the photodiode is required.